![[Datsun 1200 encyclopedia]](/wiki/upload/wiki.png)
| Revision as of 03:54, 11 April 2013 ddgonzal (Talk | contribs) <- Previous diff |
Revision as of 04:09, 11 April 2013 ddgonzal (Talk | contribs) Next diff -> |
||
| Line 2: | Line 2: | ||
| = Overview = | = Overview = | ||
| + | The stock A12 valves (35/29) are good for small-bore (1200cc) use below for up to 6000 RPM. For larger bore engines (or higher RPM) the 37/30 valves from an A14 are better. | ||
| + | |||
| + | For racing at high RPMs, more power can be made with larger valves, but care must be taken for proper valve flow. | ||
| + | |||
| The 40s may require relief/flow notch in the side of the cylinder wall? | The 40s may require relief/flow notch in the side of the cylinder wall? | ||
| Line 18: | Line 22: | ||
| = 42mm Valves = | = 42mm Valves = | ||
| - | 42 mm intakes are perhaps the limit for fitting to A-series cylinder head. | + | 42 mm intakes are perhaps the limit for A-series cylinder heads. |
| [http://datsun1200.com/modules/myalbum/photo.php?lid=20264 http://datsun1200.com/uploads/thumbs/20264.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=12142 http://datsun1200.com/uploads/thumbs/12142.jpg] | [http://datsun1200.com/modules/myalbum/photo.php?lid=20264 http://datsun1200.com/uploads/thumbs/20264.jpg] [http://datsun1200.com/modules/myalbum/photo.php?lid=12142 http://datsun1200.com/uploads/thumbs/12142.jpg] | ||
| = Dual Valve Springs = | = Dual Valve Springs = | ||
| - | Large valves work best at high RPM. When revving over 6000 RPM, dual valve springs are called for. | + | Large valves work best at high RPM. When revving over 6000 RPM, dual valve springs are called for. The stock A12GX springs are good for 6600 RPM. |
| + | |||
| + | Racing/aftermarket dual springs are usually good for 9000 RPM and shouldn't be used in a street engine as they cause accelerated wear on the valve guides. | ||
| [http://datsun1200.com/modules/myalbum/photo.php?lid=19821 http://datsun1200.com/uploads/thumbs/19821.jpg] | [http://datsun1200.com/modules/myalbum/photo.php?lid=19821 http://datsun1200.com/uploads/thumbs/19821.jpg] | ||
Revision as of 04:09, 11 April 2013
Stock valves for A12 engine are 35 mm intake, 29 mm exhaust. You can fit the A14-size 37mm inlet/30mm exhaust. And valves up to 40mm have been fitted for ultra high-RPM use.
Contents |
Overview
The stock A12 valves (35/29) are good for small-bore (1200cc) use below for up to 6000 RPM. For larger bore engines (or higher RPM) the 37/30 valves from an A14 are better.
For racing at high RPMs, more power can be made with larger valves, but care must be taken for proper valve flow.
The 40s may require relief/flow notch in the side of the cylinder wall?
Feral
Feral used 40mm steel Inlet valves, tuliped and swirl polished, with 35mm Exhausts steel polished.
42mm Valves
42 mm intakes are perhaps the limit for A-series cylinder heads.
Dual Valve Springs
Large valves work best at high RPM. When revving over 6000 RPM, dual valve springs are called for. The stock A12GX springs are good for 6600 RPM.
Racing/aftermarket dual springs are usually good for 9000 RPM and shouldn't be used in a street engine as they cause accelerated wear on the valve guides.
Triple Valve Springs
Photo Index
Big Valve
Valve Spring
